KSB PumpDrive 2 - Sleep Mode with Setpoint Increase; Restarting

8 Commissioning/Shutdown
104 of 212
PumpDrive 2
Sleep mode with setpoint increase
This sleep mode variant is active if a value larger than 0 is selected for the Setpoint
Increase parameter (3-9-4-2).
∆p
t
t
t
3
t
2
t
1
n
ab
(3-7-3-4)
n
∆p
ist
∆p
ist
∆p
soll
n
3-9-4-3
3-9-4-7
3-9-4-4
3-9-4-5
3-9-4-2
Fig.74: Sleep mode with setpoint increase (shown here by example after the stop speed has been undershot)
Δp
actual
Actual value reaches increased setpoint
Δp
actual
Actual value does not reach increased setpoint
If the low flow limit (3-4-3-30) or stop speed (3-9-4-8) of the pump is undershot due
to minimum withdrawal over the specified period (3-9-4-3), setpoint increase starts
(t1). In the process, the setpoint is increased along a ramp until it reaches the target
setpoint increase (3-9-4-2) and is maintained at a constant level. The ramp time is
defined by the Ramp-up Time for Setpoint Increase parameter (3-9-4-7). The total
duration of setpoint increase is limited by parameter (3-9-4-4). Control now targets
the increased setpoint. If the increased setpoint is reached within this time, stop is
triggered (t2). If the actual value does not reach the increased setpoint within this
time, the setpoint is reset and the stop attempt cancelled. The pump then operates
for a configurable minimum time (3-9-4-6) before another stop attempt can be
started.
Restarting
Pressure drops as soon as fluid is withdrawn. If the configurable limit value for the
Maximum Control Deviation for Restart (3-9-4-5) is achieved, the pump starts up
again (t3).
NOTE
In a multiple pump system, starting of an additional pump cancels the stop attempt.